FR3130210A1 - Low voltage power supply system for pantograph and pantograph equipped with such a system - Google Patents

Abstract

The invention consists of a low voltage power supply system intended to be mounted on a pantograph 2 and a pantograph 2 equipped with such a low voltage power supply. The power supply system according to the invention comprises a transducer converting the vibratory movement of a moving part of the head of the pantograph 4 into an electrical voltage. The friction of one or more bows 10 on the catenary 5 generates a vibration which is converted by the transducer into electric current. This transducer can be constituted by a plunger 15a moving inside an induction coil 15b or alternatively by a piezoelectric module compressed between two armatures. Figure for abstract: Fig. 1

Description

Low voltage power supply system for pantograph and pantograph equipped with such a system

The present invention relates to a low voltage power supply system intended to be installed on a pantograph for electric vehicles powered by catenaries, such as electric trains or urban passenger transport vehicles (tramway, metro, etc.).

It also relates to a pantograph equipped with such a low voltage power supply system.

The invention applies in particular to the autonomous power supply of low voltage devices on board an electric vehicle powered by catenaries and located at the level of a pantograph. Indeed, it is common for sophisticated measuring devices to be installed at the level of the pantograph to measure, during the movements of the vehicle supplied by the pantograph, various electrical, optical, thermal and mechanical parameters related to the interaction between the pantograph and the catenaries. These measurements can be used for catenary maintenance and the detection and localization of catenary problems, such as faults in the lateral positioning or mechanical tension of the catenaries. The permanent control of the catenaries by the vehicles circulating on the track makes it possible to intervene preventively before the occurrence of damage to the catenary which can cause significant interruptions to traffic.

For measuring devices to work properly, it is essential to ensure a stable and reliable low voltage supply to these measuring devices. However, the low voltage supply of these devices is not simple since the pantographs ensuring the electric power supply of the vehicles are under high voltage. Indeed, the catenary electrical voltages can range from 750 to 25,000 V in direct or alternating current, they require efficient galvanic insulation of all the electrical systems located near the pantograph. Thus, the power supply of the measuring devices poses electrical problems whose resolution is complex and expensive.

As explained below, different solutions are commonly used to ensure the low voltage power supply of devices located at the level of the pantographs.

A high voltage isolation transformer can be used for this purpose. Nevertheless, its mechanical and electrical integration on the roof of the vehicle at the level of the pantograph is delicate. Indeed, these transformers are relatively bulky and their attachment to the roof must be strong enough to withstand the mechanical stresses resulting from accelerations in all spatial directions during movement of the vehicle. These mechanical constraints are all the more important because of the consequent weight of the transformers. In addition, transformers with high voltage isolation are expensive and add a risk of high voltage short circuit in the event of failure of this one.

Battery power can also be considered. Nevertheless, this solution requires frequent access to the roof to replace the discharged batteries, requiring cuts and securing of the high voltage. In addition, a premature discharge of the batteries or a problem of replacing the batteries cannot be excluded, with the risk of losing the measurements. Solutions exist to increase the operating time of batteries such as coupling them to solar panels or a wind turbine, without completely eliminating the need to replace them regularly.

The aim of the present invention is to propose an improved low voltage power supply system to ensure the operation of the electronic devices located at the level of the pantographs which solves at least certain problems of the known solutions.

To this end, the invention relates, according to a first aspect, to a low voltage power supply system mounted on a pantograph, and comprising a transducer which converts the movement of a moving part of the pantograph into electrical energy.

Thus the power supply system according to the invention is entirely autonomous, inexpensive to produce and it requires little or no regular maintenance. In addition, this power system is independent of the vehicle's electrical power supply. It is therefore suitable for electric vehicles powered by alternating current as well as those powered by direct current.

Advantageously, in the low voltage power supply system, the transducer is an induction transducer.

Preferably, the transducer comprises a plunger mechanically connected to the moving part of the pantograph, and generating a magnetic field in an induction coil of the transducer.

Alternatively, in the low voltage power supply system, the transducer is a piezoelectric module subjected to a mechanical stress generated by said movement of the mobile part of the pantograph.

In particular, when the transducer is a piezoelectric module, the piezoelectric module is preferably located at the level of an element of the suspension of the pantograph head.

Preferably, the low voltage power supply system further comprises an electrical processing device comprising a unit for storing the electrical energy supplied by the transducer.

Thanks to these characteristics, the electrical energy generated by the transducer is stored to power the low voltage devices. In particular, the energy stored in the electrical energy storage unit can be used when the power supply system produces little or no energy, that is to say when the moving part of the pantograph is not, or barely, in motion.

The present invention relates, according to a second aspect, to a pantograph equipped with a low voltage power supply system as defined above.

Preferably, the mobile part of the pantograph is mechanically connected to a bow of the pantograph.

More specifically, the transducer converts the mechanical energy generated by vibratory movements of the pantograph

Said vibratory movements are, in general, complex vibratory movements caused by the movements of the elements of the pantograph, and/or of its internal moving parts, and/or and of the catenary. Generally, said vibratory movements are a combination of linear and/or rotary movements, in one or more spatial directions.

In particular, said vibratory movements are caused by the friction of the bow on a catenary.

Preferably, said vibratory movements are linear, substantially vertical. Alternatively, said vibratory movements are substantially rotary.

Alternatively, the transducer converts the mechanical energy generated by the oscillatory movements of a pantograph head to at least two archers.

The pantograph has characteristics and advantages similar to those previously described in relation to the supply system.

Other characteristics and advantages of the invention are highlighted by the description below of non-limiting examples of embodiments of the various aspects of the invention. The description refers to the appended figures which are also given by way of non-limiting embodiment examples of the invention:

there schematically represents a first type of pantograph equipped with an induction coil,

there schematically represents a first type of pantograph equipped with a piezoelectric ceramic,

there schematically represents a second type of pantograph equipped with an induction coil, and

there schematically represents a second type of pantograph equipped with a piezoelectric ceramic.

In order to monitor the operation of the pantographs ensuring the supply of electrical power to vehicles, such as, for example, train locomotives, self-propelled railway vehicles, or trams, and the condition of the catenaries under which the pantographs are in contact , electrical devices are mounted on the roof of these vehicles at the level of the pantograph.

There represents a roof 1 of a locomotive on which is mounted a pantograph 2 via electrical insulators 3. The pantograph 2 is an articulated device which can either be in the folded position or in the erected position. It is in this erect position, as shown in , that the pantograph can capture the electric current ensuring the power supply of the locomotive by friction of a pantograph head 4 on a catenary 5.

In electric railway equipment, the pantographs usually had the shape of a diamond. Nowadays, modern pantographs only consist of a lower arm 6 connected in an articulated manner to an upper arm 7. On the one hand, the lower arm 6 is mechanically connected by one of its ends to the roof 1 of the locomotive , via a first joint 8. The arm 6 is insulated from the roof 1 of the locomotive by means of the insulators 3. On the other hand, it is connected by its other end to one of the ends of the upper arm 7, via a second joint 9 The upper arm 7 supports at its other end the pantograph head 4. Modern pantographs can have a range of vertical movement of up to 3.8 meters. The pantograph is actuated to pass from the folded position to the erected position by a lifting device (not shown) which may be pneumatic or electric, the return to the folded position generally taking place by gravity.

The pantograph head 4 comprises a bow 10 which rubs against the catenary 5 when the pantograph 2 is in the erected position. A rubbing strip (not shown) generally made of carbon is mounted on the upper face of the archer 10 in order to rub against the catenary 5 to capture the electric current passing through it. A control device ensures that the lifting device of the pantograph 2 generates a controlled pressure of the bow 10 on the catenary 5. Nevertheless, in order to compensate for differences in height of the catenary 5 on the path of the locomotive and the presence on the catenary 5 of elements necessary for its suspension, the pantograph head 4 comprises a suspension 11 movably connecting the bow 10 to the upper arm 7 of the pantograph 2.

The unevenness of the catenary 5 as well as its mechanical defects generate a substantially vertical vibratory movement 12 which is amplified by the speed of the train. This substantially vertical vibratory movement 12 is compensated by the suspension 11 which prevents the detachment of the bow 10 from the catenary 5. Indeed these detachments generate electric arcs which are harmful for the behavior of the catenary and the friction strip, which generate electromagnetic interference. Loss of contact between the bow and the catenary can cause the traction chain to stop

One or more electrical devices 13 are mounted in the vicinity of the first joint 8 of the lower arm 6 of the pantograph 2, or at any other place on the pantograph 2. These electrical devices 13 can perform different functions. These are most often measurement systems supplied with low voltage.

In the exemplary embodiment of the invention illustrated in , the electric current required for this low-voltage power supply is generated by an induction transducer 15 converting the substantially vertical vibrations 12 of the bow 10 into electrical energy.

The low voltage electric current generated by the induction transducer 15 is rectified and managed by an electric processing device 14 before supplying the electric devices 13.

The electrical processing device 14 is composed for example of a rectifier system and of a storage unit for the electrical energy supplied by the induction coil 15b.

It further comprises a controller which manages the electrical energy thus generated as well as the inner workings of the low voltage power supply system described above so that it can power any kind of electrical device 13.

The induction transducer 15 comprises a plunger 15a generating a magnetic field, such as a ferromagnetic plunger or a magnet, mechanically connected to a first movable part 16 of the suspension 11 attached to the bow 10. The induction transducer 15 also comprises a coil induction 15b mechanically connected to a second part 18 of the suspension 11 connected to the upper arm 7 of the pantograph 2. The vibratory movement 12 of the bow 10 relative to the upper arm of the pantograph is transmitted to the first part 16 of the suspension 11 which drives the plunger 15a which in turn vibrates inside the induction coil 15b. Thus the vertical vibratory movement 12 is converted into electrical energy which is transmitted by an electrical connection to the electrical processing device 14, the latter being able to be located either at the base of the pantograph or in the immediate vicinity of the induction transducer 15. In particular, when the induction transducer and the electrical processing device 14 are distant, the electrical connection takes the form of a wiring 19, which can be guided along the lower arm 6 and upper arm 7.

There shows a second embodiment of the invention in which the induction transducer is replaced by a piezoelectric transducer consisting of a piezoelectric module 20.

In this exemplary embodiment of the invention, it is the direct piezoelectric effect, that is to say the polarization of a piezoelectric component when it is placed under stress, which is used to generate energy. electric.

As shown in , the piezoelectric module 20 is mounted between a first armature 21 mechanically connected to the second part of the suspension 18 and a second armature 22 mechanically connected to the end of the upper arm 7 opposite to that connected to the second articulation 9. The piezoelectric module may be made of a piezoelectric ceramic or other piezoelectric materials, such as piezocomposites.

When the locomotive moves under the catenary 5, the vertical vibratory movement 12 of the bow 10 is transmitted to the suspension 11. This vertical vibratory movement 12 is transmitted to the first armature 21 which thus compresses the piezoelectric module 20 against the second armature 22. This mechanical compression of the piezoelectric module is converted into a voltage which generates a current transmitted to the electrical processing device 14 by the electrical connection, in order to supply the electrical device 13.

There shows a second type of pantograph 2 in which the pantograph head 4 is provided with two bows 10 rubbing simultaneously on the catenary 5. The two bows 10 are mechanically fixed to an oscillating suspension 23 connected by a third articulation 24 to the end of the upper arm 7 opposite to that connected to the second articulation 9. Elastic connections 25 mechanically connect the third articulation 24 to mobile suspension arms 26. These elastic connections can comprise helical springs, conical elastic washers, or any other elastic element allowing compression and axial expansion between the suspension arm 26 and the third joint 24. Each suspension arm 26 is mechanically connected to one of the bows 10.

In a variant not shown, each suspension arm 26 may include a vertical suspension similar to that of the pantograph head 4 illustrated in Figures 1 and 2.

In the exemplary embodiment illustrated in , the transducer is constituted on the one hand by an induction coil 15b mechanically connected to the end of one of the elastic links 25 located on the side of the third articulation 24, and on the other hand by a plunger 15a generating a magnetic field , such as a ferromagnetic plunger, mechanically connected to the other end of the elastic connection 25 located on the side of the suspension arm 26.

In a variant not shown, an induction coil 15b and a plunger 15a can be mounted on each of the elastic links 25.

In this context, the mechanical irregularities and unevenness of the catenary 5 generate vibrations at the level of the bows 10 which cause the oscillating suspension 23 to oscillate around the third articulation 24 and to compress and relax the elastic connections 25. These compression movements / relaxation 27 of the elastic links 25 cause the plunger 15a to vibrate inside the induction coil 15b. The vibration of the plunger is converted into a current in the induction coil 15b which is transmitted by the electrical connection to the electrical device 13 via the electrical processing device 14. If necessary, the plunger 15a and the induction coil 15b mounted on an electrical connection elastic 25 can be doubled by a second plunger/coil assembly mounted on the other elastic link 25. This device with one or two induction transducers mounted on the elastic links 25 can also be supplemented by an induction transducer device mounted on a or the two suspension arms 26 as shown in Figures 1 and 2.

A low-voltage power supply concept is thus obtained that can be adapted to different levels of electrical power to power different types of electrical devices 13.

There shows another embodiment of a low voltage power supply for a pantograph 2 with double bows 10 in which one or both suspension arms 26 comprise a piezoelectric module 20 mounted between a first armature 21 mechanically connected to the end of the suspension arm 26 located on the side of the bow 10 and a second frame 22 located on the side of the suspension arm 26 connected to the corresponding elastic connection 25. Alternatively, the configuration of the piezoelectric device illustrated in can also be used as a variant for a pantograph 2 with double bows 10 as illustrated in . The piezoelectric module 20 can be of the same type as that described above in relation to the .

In this context, the mechanical irregularities and unevenness of the catenary 5 generate on the one hand vibrations at the level of the bows 10 which cause the oscillating suspension 23 to oscillate around the third articulation 24 and on the other hand mechanical compression stresses in the suspension arms 26 which compress the piezoelectric module 20.

Thus, the mechanical stresses induced in the piezoelectric module 20 generate a current which is transmitted to the electrical device 13 by the electrical connection via the electrical processing device 14.

Inductive transducers or piezoelectric transducers are commonly used devices that are cheap and easy to implement. Once installed, the low voltage power systems described above are reliable and require little or no maintenance, resulting in operating savings. In addition, as indicated above, a pantograph can be equipped with one or more transducers of the same category, or a combination of induction and piezoelectric transducers mounted on the elastic links 25 and/or on the suspension arms 26 and /or any other part of the pantograph generating a movement. Thus, the description given above does not limit the use of energy harvesting to a single technology (induction or piezoelectric). The use of both at least one induction transducer and at least one piezoelectric transducer can be envisaged to further increase the amount of energy recovered. Similarly, the description does not limit the arrangement of the transducer(s), whether induction and/or piezoelectric, at the level of the pantograph head. For example, it is possible to arrange a transducer at the angle formed between the arms 6 and 7 of the pantograph, in particular at the level of the joint 9, so as to convert the rotary movement at the level of said joint into electrical energy. . In the same way, it is possible to have a transducer at the level of joint 8.

Such an arrangement of a transducer is particularly advantageous when the pantograph 2 comprises one or more rotary suspensions, for example arranged at the joint 9 between the arms 6 and 7 of the pantograph.

Although in the description above the particular aspects of the invention, in particular the implementation of one or more transducers, have been described in the context of an electric traction locomotive powered by an alternating or direct voltage transmitted by pantograph and catenary, they could be implemented in other configurations, in particular with other types of transport vehicles, such as for example urban passenger transport vehicles such as trams or trolleybuses.

Claims (10)

Low voltage power system mounted on a pantograph (2), characterized in that it comprises a transducer (15, 20) converting the movement of a moving part (16, 26) of the pantograph into electrical energy. Low-voltage power supply system according to Claim 1, characterized in that the transducer (15) is an induction transducer. Low voltage power supply system according to claim 2, the transducer (15) comprising a plunger (15a) mechanically connected to the movable part (16) of the pantograph (2), and generating a magnetic field in an induction coil (15b) of the transducer (15). Low voltage power supply system according to Claim 1, characterized in that the transducer is a piezoelectric module (20) subjected to a mechanical stress generated by said movement of the mobile part (16, 26) of the pantograph (2). Low-voltage power supply system according to Claim 4, characterized in that the piezoelectric module (20) is located at the level of an element of the suspension of the head (4) of the pantograph (2). Low voltage power supply system according to any one of the preceding claims, characterized in that it further comprises an electrical processing device (14) comprising a unit for storing the electrical energy supplied by the transducer (15, 20 ). Pantograph (2) equipped with a low voltage power supply system according to one of the preceding claims. Pantograph (2) according to Claim 7, characterized in that the movable part (16, 26) of the pantograph (2) is mechanically connected to a bow (10) of the pantograph (2). Pantograph (2) according to Claim 8, in which the transducer (15, 20) converts the mechanical energy generated by vibratory movements (12), preferentially caused by the friction of the bow (10) on a catenary (5) . Pantograph according to Claim 8, in which the transducer (15, 20) converts the mechanical energy generated by the oscillatory movements of a pantograph head (4) to at least two bows (10).
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